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JAEA Reports

Investigation on soundness of JMTR Facility piping by ultrasonic thickness measurement

Omori, Takazumi; Otsuka, Kaoru; Endo, Yasuichi; Takeuchi, Tomoaki; Ide, Hiroshi

JAEA-Review 2021-015, 57 Pages, 2021/11

JAEA-Review-2021-015.pdf:6.3MB

The JMTR reactor facility was selected as a decommissioning one in the Medium/Long-Term Management Plan of JAEA Facilities formulated on April 1, 2017. Therefore, the decommissioning plan was submitted to Nuclear Regulation Authority on September 18, 2019, and the approval was obtained on March 17, 2021 after two amendments. Currently, preparations for decommissioning are underway. The JMTR reactor facility has been aged for more than 50 years since the first criticality in March 1968. However, some of the water piping systems has not been updated since its construction, and there is a possibility of pipe wall thinning due to corrosion, etc. Therefore, the integrity of the water piping was investigated for the facilities that circulate cooling water and pump radioactive liquid waste. In this investigation, the main circulation system of the reactor primary cooling system, the pool canal circulation system, the CF pool circulation system, the drainage system of the liquid waste disposal system, and the hydraulic rabbit irradiation system of the main experimental facility were measured for the pipe wall thickness using the Ultrasonic Thickness Measurement (UTM) method. These values satisfied the technical standards for research and test reactor facilities. No loss of integrity is expected to occur during the upcoming decommissioning period. In the future, we will periodically confirm that there is no wall thinning in the piping of the cooling water circulation and the water transmission system during the decommissioning period by using this result as basic data.

Journal Articles

Development of laser cutting technology of thick steel plates for nuclear facilities

Tamura, Koji*; Toyama, Shinichi

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 62(5), p.268 - 271, 2020/05

The laser cutting technology is expected to be a promising candidate for the decommissioning measure of nuclear facilities, because it has a lot of advantage such as its high controllability and excellent suitability to remote handling by robot arm, etcetera. This report describes the recent result from laser cutting technology development for thick steel materials summarizing the cutting demonstration of 300 mm thick steels and dummy pressure vessel, the analysis of cutting condition of thick steel cutting, the observation of cutting process, remote controlled cutting system, the cutting in pile of steels by the system, and countermeasure for fume produce by cutting process.

Journal Articles

Failure behavior analyses of piping system under dynamic seismic loading

Udagawa, Makoto; Li, Y.; Nishida, Akemi; Nakamura, Izumi*

International Journal of Pressure Vessels and Piping, 167, p.2 - 10, 2018/11

 Times Cited Count:5 Percentile:50.42(Engineering, Multidisciplinary)

It is important to assure the structural Integrity of piping systems under severe earthquakes because those systems comprise the pressure boundary for coolant with high pressure and temperature. In this study, we examine the seismic safety capacity of piping systems under severe dynamic seismic loading using a series of dynamic-elastic-plastic analyses focusing on dynamic excitation experiments of 3D piping systems which was tested by NIED. Analytical results were consistent with experimental data in terms of natural frequency, natural vibration mode, response accelerations, elbow opening-closing displacements, strain histories, failure position, and low-cycle fatigue failure lives. Based on these results, we concluded that the analytical model used in the study can be applied to failure behavior evaluation for piping systems under severe dynamic seismic loading.

Journal Articles

A Study of methods to prevent piping and erosion in buffer materials intended for a vertical deposition hole at the Horonobe Underground Research Laboratory

Jo, Mayumi*; Ono, Makoto*; Nakayama, Masashi; Asano, Hidekazu*; Ishii, Tomoko*

Geological Society Special Publications, 482, 16 Pages, 2018/09

 Times Cited Count:1 Percentile:17.46

Journal Articles

Cost performance design for high temperature helium heat transport piping of GTHTR300C and HTTR-GT/H $$_{2}$$ plants

Nomoto, Yasunobu; Horii, Shoichi; Sumita, Junya; Sato, Hiroyuki; Yan, X.

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 9 Pages, 2017/04

This paper presents the cost performance design of heat transport piping systems for GTHTR300C plant and HTTR-GT/H $$_{2}$$ plant. Two types of pipe structure are designed and compared in terms of cost performance. Relative to the coaxial double-pipe structure, the insulated single pipe structure is found to have the advantage in overall cost performance considering both the material quantity and the heat loss because it reduces the quantity of steel used for construction. Furthermore it is possible to reduce the heat loss and temperature reduction of hot helium gas by the attachment of the external insulation. The pressure tube made of type-316 stainless steel with high-temperature strength is possible to achieve the same temperature reduction by smaller diameter than that made of 2 1/4Cr-1Mo steel. It contributes to the reduction of the quantity of steel. Specifications of heat transport piping systems for both plants are determined according to these study results.

Journal Articles

Influence of inlet velocity condition on unsteady flow characteristics in piping with a short elbow under a high-Reynolds-number condition

Ono, Ayako; Tanaka, Masaaki; Kobayashi, Jun; Kamide, Hideki

Mechanical Engineering Journal (Internet), 4(1), p.16-00217_1 - 16-00217_15, 2017/02

In the design of the Advanced Sodium-cooled Fast Reactor in Japan, the Reynolds number in the primary hot leg (H/L) piping reaches 4.2$$times$$10$$^{7}$$. Furthermore, a short elbow is used in the H/L piping to achieve a compact plant layout. In the H/L piping, flow-induced vibration is a concern due to the excitation force caused by pressure fluctuation in the short elbow. In this report, the influence of inlet velocity condition on the unsteady velocity characteristics in the short elbow was studied by controlling the flow patterns at the elbow inlet. Measured velocity distributions indicated that the inlet velocity profiles affected a circumferential secondary flow, which then affected an area of flow separation at the elbow. It was also found that the velocity fluctuation at low frequency components observed upstream of the elbow could remain in downstream of the elbow though its intensity was attenuated.

Journal Articles

The Effect of profile of inlet velocity on the pressure fluctuation on the inside wall of short-elbow

Ono, Ayako; Tanaka, Masaaki; Kobayashi, Jun; Kamide, Hideki

Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 7 Pages, 2014/11

Journal Articles

Development of structural reliability evaluation method for aged piping considering uncertainty of seismic motions

Sugino, Hideharu*; Ito, Hiroto*; Onizawa, Kunio; Suzuki, Masahide

Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(4), p.233 - 241, 2005/12

The purpose of this research is to establish the reliability evaluation method of aged nuclear power components for seismic events from a viewpoint of long-term use of the existing light water reactor nuclear power plants. For this purpose, we developed a piping failure probability evaluation code "PASCAL-SC" based on probabilistic fracture mechanics, and a probabilistic seismic hazard evaluation code "SHEAT-FM" for calculating the seismic occurrence probability of a plant site, paying attention to aging such as fatigue crack progress by the stress corrosion cracking and seismic load in primary coolant piping system. We proposed the reliability evaluation method of aged piping for seismic events by combination of these codes. Using this method, we evaluated the reliability of a weld line in the PLR(Primary Loop Recirculation system) piping of the BWR model plant for seismic events.

JAEA Reports

Development of measuring device for inner surfaces of embedded piping (Contract research)

Ito, Hirokuni*; Hatakeyama, Mutsuo*; Tachibana, Mitsuo; Yanagihara, Satoshi

JAERI-Tech 2003-012, 34 Pages, 2003/03

JAERI-Tech-2003-012.pdf:2.87MB

The MISE was developed to evaluate low-level radiological contaminations of inner surfaces of piping. The MISE consists of a cylindrically-formed double layered type detector and a piping crawling robot, which were designed and manufactured separately. In measurements of the contaminations, an outer cylindrical detector close to the surface of piping measures $$beta$$-rays and $$gamma$$-rays and an inner cylindrical detector set after a shielding plate for shield of $$beta$$-rays measures $$gamma$$-rays. The $$beta$$-ray counting rates are derived by subtracting $$gamma$$-ray counts measured by the inner detector from $$gamma$$- and $$beta$$-ray counts measured by the outer detector. The robot transports the double layered type detector with observing inner surfaces of piping. The detection limit for the contamination of $$^{60}$$Co was found to be about 0.17Bq/cm$$^{2}$$ with measurement time of 30 seconds. It is expected that 0.2Bq/cm$$^{2}$$ corresponding to clearance level of $$^{60}$$Co (0.4Bq/g) can be evaluated with measurement time of 2 seconds, which is equal to measurement speed of 54m/h.

Journal Articles

Creep failure of reactor cooling system piping of nuclear power plant under severe accident conditions

Chino, Eiichi; Maruyama, Yu; Maeda, Akio*; Harada, Yuhei*; Nakamura, Hideo; Hidaka, Akihide; Shibazaki, Hiroaki*; Yuchi, Yoko; Kudo, Tamotsu; Hashimoto, Kazuichiro*

Proceedings of the 7th International Conference on Creep and Fatigue at Elevated Temperatures (CREEP7), p.107 - 115, 2001/06

no abstracts in English

Journal Articles

Revaporization of CsI aerosol in a horizontal straight pipe in a severe accident condition

Shibazaki, Hiroaki*; Maruyama, Yu; Kudo, Tamotsu; Hashimoto, Kazuichiro*; Maeda, Akio*; Harada, Yuhei*; Hidaka, Akihide; Sugimoto, Jun

Nuclear Technology, 134(1), p.62 - 70, 2001/04

 Times Cited Count:3 Percentile:27.65(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Post-test creep analysis of piping failure tests in WIND project

Chino, Eiichi; Maruyama, Yu; Yuchi, Yoko; Shibazaki, Hiroaki*; Nakamura, Hideo; Hidaka, Akihide; Kudo, Tamotsu; Hashimoto, Kazuichiro; Maeda, Akio*

JAERI-Conf 2000-015, p.303 - 308, 2000/11

no abstracts in English

Journal Articles

Vapor condensation and thermophoretic aerosol deposition of cesium iodide in horizontal thermal gradient pipes

Maruyama, Yu; Shibazaki, Hiroaki*; Igarashi, Minoru*; Maeda, Akio; Harada, Yuhei; Hidaka, Akihide; Sugimoto, Jun; Hashimoto, Kazuichiro*; Nakamura, Naohiko*

Journal of Nuclear Science and Technology, 36(5), p.433 - 442, 1999/05

 Times Cited Count:9 Percentile:58.21(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Three-dimensional analysis on thermo-fluiddynamics in piping with WINDFLOW

Maruyama, Yu; Igarashi, Minoru; Nakamura, Naohiko; Hidaka, Akihide; Hashimoto, Kazuichiro; Sugimoto, Jun; Nakajima, Kengo*

JAERI-memo 08-127, p.233 - 238, 1996/06

no abstracts in English

Journal Articles

Three-dimensional thermo-fluiddynamic analysis of gas flow in straight piping with WINDFLOW code

Maruyama, Yu; Igarashi, Minoru*; Nakamura, Naohiko; Hidaka, Akihide; Hashimoto, Kazuichiro; Sugimoto, Jun; Nakajima, Kengo*

Proc. of ASME$$cdot$$JSME 4th Int. Conf. on Nuclear Engineering 1996 (ICONE-4), 1(PART B), p.997 - 1008, 1996/00

no abstracts in English

Journal Articles

Experimental study on aerosol deposition in horizontal straight piping

Maruyama, Yu; Igarashi, Minoru*; Hashimoto, Kazuichiro; Nakamura, Naohiko*; Hidaka, Akihide; Sugimoto, Jun

Transactions of the American Nuclear Society, 75, p.273 - 274, 1996/00

no abstracts in English

Journal Articles

Experimental and analytical study on the behavior of cesium iodide aerosol/vapor deposition onto inner surface of pipe wall under severe accident conditions

Hidaka, Akihide; Igarashi, Minoru*; Hashimoto, Kazuichiro; ; *; Sugimoto, Jun

Journal of Nuclear Science and Technology, 32(10), p.1047 - 1053, 1995/10

 Times Cited Count:13 Percentile:76.97(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Influence of wetting effect at the outer surface of the pipe on increase in leak rate; Experimental results and discussion

Isozaki, Toshikuni; Shibata, Katsuyuki

LBB95: Specialist Meeting on Leak Before Break in Reactor Piping and Vessels, 0, 10 Pages, 1995/00

no abstracts in English

Journal Articles

Analysis of reactor piping behavior against thermal loads during severe accident

Hashimoto, Kazuichiro; Nakamura, Naohiko; Igarashi, Minoru*; Maruyama, Yu; Sugimoto, Jun

The 3rd JSME/ASME Joint Int. Conf. on Nuclear Engineering, Vol. 3, 0, p.1241 - 1246, 1995/00

no abstracts in English

Journal Articles

Results of reliability test program on light water reactor piping

Shibata, Katsuyuki; Isozaki, Toshikuni; Ueda, Shuzo; Kurihara, Ryoichi; Onizawa, Kunio; Kosaka, Atsuo

Nucl. Eng. Des., 153, p.71 - 86, 1994/00

 Times Cited Count:10 Percentile:66.93(Nuclear Science & Technology)

no abstracts in English

34 (Records 1-20 displayed on this page)